Tool



April 29, 1941.

R. H. KINGDON ET AL' 3 Sheets-Sheet 1 "w I0 re.

T e .R 0 0 I m}. A 4 q a 5 MN Ava W S l T April 29, 1941. R. H. KINGDON ETAL 2,240,188

TOOL

Filed March 30, 1940 3 Sheets-Sheet 2 Patented Apr. 29,1941

UNITED STATES PATENT o FFICE iroor. Ralph H. Kingdon and George K. Moore, Detroit,

Mich, assignors to Square D Company, Detroit,

Mich, a corporation of Michigan Application March so, 1940, Serial No. 327,084

8 Claims. (01. 164-86) This invention relates to a punch and die tool for forming, in a single pressing operation the opening providing means in the walls of the enclosing box for an electrical instrumentality' which shall permit the optional selection of a plurality of different size openings to optionally tially tangent at one point.

Other objects and features -of this invention vide the desired size opening. These sections include the inner disc section 4 removable to receive the smallest size conduit and scored about its entire outline, except for the tying portion which holds the section in place until the tie is forcibly broken by bending or other manipulation I, when an opening is desired. Outside of the section 4, there is a larger ring section 6, which is scored about its exterior outline except at the top and bottom tie points I and 8. Beyond the section 6, there is a crescent shaped section 9 v provided with a full tie at II! and partial ties at II and. I2, the ties I l and I2 being slightly nicked in the forming operation to make these ties more frangible than the other ties provided. The

. largest opening in the wall is provided by the exwill be readily apparent to those skilled in the art from the specification and appended drawings illustrating certain preferred embodiments in which:

Figure 1 is an elevational view of portions cut away of the enclosing box having opening providing means therein, with the smallest se'ction removed to receive a conduit of the smallest size.

. Figure 2 is an enlarged sectional view on the lines IIII of Figure 1.

Figure 3 is a sectional view on the lines III- III of Figure 2. a

Figure 4 is a detail sectional view on the lines IV-IV of Figure 3.

Figure 5 is a perspective view of one of the opening providing means.

Figure 6 is a sectional view of the punch and die tool which forms the opening providing means shown in the preceding figures.

Figure '7 is a sectional view on the lines VII VII of Figure 6.

Figure 8 is a view similar to Figure 6, withcertain parts broken away and with the punch shown in retracted or open position.

Figure 9 is an enlarged detail sectional view on the lines IX-IX of Figure 8.

Figure 10 is an enlarged detail sectional view on the lines XX of Figure 8.

Figure 11 isan enlarged detail sectional Viewv on the lines XIX[ of Figure 10.

In the drawings, in which like reference numerals indicate like parts, there is shown an enclosing box I for an electric circuit instrumentality generally indicated at 2. In the wall of the box, there is shown opening providing means indicated generally at 3 and composed of a plurality of sections integral with the ,box wall, but scored to be readily removable therefrom to proterior boundary of the crescent shaped section I3 similarly scored throughout its outline, except at ties I4 and I5. The lower portion of ring section 6 follows the outline of section I3 to the ties and I2 so that the crescent shaped section has ends of substantial width. Figures 1 to 4 inclusive show the smallest section 4 removed and a conduit I6 inserted through the opening in the box wall provided by the removal of the sections and maintained in place by interior and exterior locking nuts I8 and I1.

With the opening providing means thus described, it is seen that there are provided a plurality of sections which, when removed, leave substantially circular openings within the box wall for the reception of conduit. These sections are all scored to be readily removable but are provided with small tying portions at points on their exterior outlines which securely maintain sections which it is not desired to remove in place: while still being readily frangible by bending or other manipulations when the section is desired to be removed. It is seen that certain of the exterior outlines of the sections are non-concentric and are substantially tangent at thepoint nearest the back wall of the box. 'The sections 6, 9, and I 3 have outlines which, if extended, would clearly be tangent at this point. Section 4, however, does not have its outline thus tangent to the others in view of the small width of section 6 which would cause the elements of the tie to be too thin for practical working operation if the section 4 were brought down into absolute tangency. However, the very fact which causes the small width of section 6 also renders this discrepancy in section 4 relatively immaterial, since the deviation is wellwithin allowable tolerances.

Furthermore, from the standpoint of the align- I ings in smaller opening providing means in shallow boxes, sections 4 and 6 conform quite closely to the placing of such other opening providing means so that the conduit of the smaller size extending between small boxes of different form opening providing means will align to facilitate the connection.

The tools for forming the non-concentric section outlines in a single scoring operation are illustrated in Figures 6 toll inclusive. This tool comprises cooperating punch and die elements indicated generally at 2|, 22. These elements are mounted within a press in a well-known manner and the reciprocation of the punch element produces the working operation upon the sheet metal forming'the box enclosure. In the description of the elements of the punch parts referred to as relatively stationary and relatively movable, this does not refer to the normal movement of the punch as a unit in the press, but to be the relative movement or non-movement of sections of the punch with respect to punch element itself. The punch or upper portion of the forming tool comprises a punch holder 23 having a plurality of movable stripper screws 24 therethrough which are threaded at their lower ends into a movable stripper plate 25. A recess 26 is provided within the bottom face of the punch holder in. which is disposed a movable knockout plate 21 having secured thereto and depending therefrom movable knockout pins 28 and having secured at a central portion andextending upwardly therefrom the main punch stripper pin 29. Against the under surface of the punch holder 23 are rigidly secured the stationary punch sections 3| and 32 which have the depending portions 33 and 34 which cooperate with the die element to be hereinafter described to form the sections 6 and [3. Between the portions 33 and 34 is disposed a movable punch section called the upper knockout bushing 35 having an upper flange portion 36 disposed in a clearance opening 31 between the punch sections 3| and 32. Knockout pins 38 slidably extend through the punch section 3| into engagement withthe flange 35 and are engaged at the upper ends by the knockout plate 21 to effect movement of the knockout bushing 35. Within the punch section 33 is the movable knockout punch 39 extending entirely through the punch section 3| and engaged-at its upper end by the knockout plate 21 to be moved thereby. I

The die element 22 of the tool comprises the die bushing 4| having mountedthereupon the exterior die section 42. Within the die section and a recess in the upper face of the die bushing are disposed stationary interior die sections 43 and 44 with the sections 44 having an upstanding central portion 45 corresponding to the knockout punch 39 and with the section 43 having an upstanding portion 45 corresponding to the upper knockout bushing 35. Between the portions 45 and 46 isdisposed the lower knockout bushing 41 corresponding in contour to the depending portion 33 of the punch section 3| and having a flanged lower end 48 disposed in a clearance opening 49 in the section 43 so as to be relatively movable with respect thereto. Stripper pins 5| are provided having their upper ends bearing against the flange portion 48 and their lower ends secured in an exterior stripper plate 50. At the outside of the portion 45 is a second lower knockout bushing 52 corresponding in contour to the depending portion 34 on the punch section 32 and having a lower flange portion 53 disposed in the clearance opening 54 in the exterior die sec tion 42 so as to be movable with relation thereto and having its flange portion 53 engaged by the die stripper pins 55 also secured in the die stripper plate 50. An opening is provided. in the stripper plate 50 through which extends a rod 56 threaded into the die bushing 4| and carrying a spring 51 hearing against the lower surface of the plate 52 for effecting movement thereof and of the lower knockout bushings when the punch is moved upwardly. Keys 58 and 59 are provided for preventing rotation of the punch and die parts.

From Figure 9 it is seen that depending portion 34 which forms the section I3 is so formed as to .leave an opening in the punch parts corresponding to the ties at H and I2; however, the die section, in order to properly form and nick these parts, has its knockout bushing 52 formed similarly to the upper punch section and, in addition, is provided with fill-in parts for the discontinuous portion in the form of key shaped elements 6|, disposed in the die section 42 and provided with lugs 62 in which are threaded studs 53 to secure them in place.

In the central sectional view taken for Figures 6 and 8, the portions of the punch and die which form the ties l4 and I5 are shown. These include clearance notches provided in the edge of the die section 42, as at 64. Immediately above these clearance notches, the lower edge of the depending portion of the punch section 34 is similarly provided with notches 65, the notches cooperating to leave the unscored tie portions. The tie-forming notch portions in the die parts are also shown in the plan portion of Figure 10 where they have been numbered 64, the partial tie at H and I2 being formed by the coaction between the elements BI and the clearance portions in the punch.

The operation of the tool for forming the opening providing means will be apparent from the previous description. .The sheet metal is inserted between the punch and die when the punch I is in the open position shown in Figure 8, whereupon the press is operated to depress'the punch into the position shown in Figure 6. In this operation, the movable elements of the punch embodying the stripper plate 25 and the upper knockout bushing 35 and knockout punch 39 will be moved upwardly with respect to the relative stationary parts of the punch as they encounter portions of sheet metal backed up by the stationary die sections, and similarly, the lower knockout bushings will move downwardly out of the plane of the plate by the stationary punch sections. In this operation, the sections i3 and 6 will be moved away from the normal plane of the sheet metal plate from which they are formed, their outlines, except for the ties, being entirely cut away from the main body of the plate in the desired manner.

As the punch is retracted from the position of Figure 6, the lower knockout bushings 41 and 52 will move upwardly under the bias of spring 5'! to strip the sheet metal plate from the die section. The sheet metal work plate will ordinarily move upwardly with the punch section until the punch stripper pin 29 is engaged by a stationary part on the press in well known manner, whereupon the knockout plate 21 is depressed to effect movement of the stripper plate 25, upper knockout bushing 35 and knockout punch 39 to strip the work plate from the punch for removal.

When removed from the die, the opening providing means will retain substantially the relation shown in Figure 6 and ordinarily a further pressing operation between flat die plates is provided in which the pressed out sections are pressed partially back toward their original position. This is indicated from a comparison of Figure 6 wherein the sections are entirely removed from the plate of the original plate to Figure 2 in which the sections have been pressed the majority of the distance back into position. This provides a neater and smoother arrangement while maintaining the scoring or shearing of the sections which provides for their ready removal.

While certain preferred embodiments of this invention have been specifically disclosed, it is understood that the invention is not limited thereto, as many variations will be readily apparent to those skilled in the art and the invention is'to be given its broadest possible interpretation within the terms of the following claims.

What is claimed is:

1. In a punch and die tool for forming an opening providing means in a single pressing operation in a sheet metal box for an electric instrumentality composed of a plurality of sections scored from the box wall so as to be readily removable therefrom, a stationary die element formed of a plurality of sections including. an outer section having a circular opening therein corresponding to the outer outline to be scored, a discontinuous second section received within said opening, a third section within said second section and having its exterior surface substantially tangent to the projected exterior surface of the second section and tothe interior surface of said opening at the samepoint, certain of said sections bein relatively movable, and a movable punch section formed of a plurality of sections similar and complementary to the die sections, with the sections on the. punch cooperating with stationary die sections being movable relative to the main body of the punch and with the sections on the punch cooperating with movable die sections being stationary with respect to the main body of the punch, the relative movement between said sections being sufficient to produce at least a partial shearing of the sheet metal at the cutting edges of the sections.

2. In apunch and die tool for forming an opening providing means in a single pressing operation in a sheet-metal box for an electric instrumentality composed of a plurality of sections scored from the box wall so as to be readily removable therefrom, a stationary. die element formed of a plurality of sections including an outer stationary section having a circular opening therein, a movable section substantially crescent-shaped in cross section within said p ning, a stationary section substantially crescent-shaped in cross section within said first crescent-shaped section, a movable section sub stantially ring-shaped in cross section within said stationary crescent-shaped section, and a stationary solid round section, the exterior surface of the ring shaped section and the projected exterior surface of the stationary crescent shaped section being substantially tangent to the interior surface of said circular opening and to the projected exterior surface of the movable crescent shaped section at the same point, and a main body. of the punch and with the sections on the punch cooperating with movable die sections being stationary with respect to the main body of the punch, the relative movement between said sections being sufficient to produce at least a partial shearing of the sheet metal at the cutting edges of the sections.

3. In a punch and .die tool for forming an opening providing means in a single pressing operation in a sheet metal box for an electric instrumentality composedof a plurality of sections scored from the box-wall so as to be readily removable therefrom, a stationary die element formed 'of a plurality of sections including an outer stationary section having a circular opening therein, a movable section substantially crescent-shaped in cross section within'said opening, a stationary section substantially crescentshaped in cross section within said first crescentshaped section, a-movable section substantially ring-shaped in cross section within said stationary crescent-shaped section, and a stationary solid round section within the ring-shaped section, the exterior surface of the ring shaped section and the projected exterior surface of the stationary crescent shaped section being substantially tangent to the interior surface of said circular opening and to theprojected exterior surface of the movable crescent shaped section at the same point, and a movable punch element formed of plurality of similar and complementary sections with the sections on the punch cooperating with stationary die sections being movable movable punch element formed of a plurality for similar and complementary sections with the sections on the punch cooperating with stationary die sections being movable relative to the relative to the main body of the punch and with the sections on the punch cooperating with movable die sections being stationary with respect to the main body of the punch, the cooperating cutting edges of said sections having complementary clearance recesses at predetermined points to provide integral ties for the removable outlines formed in the box wall, the relative movement between said sections being suflicient to produce at least a partial shearing of the sheet metal at the cutting edges of the sections.

4. In a punch and die tool for forming an opening providing means in a single pressing operation in a sheet metal box for an electric instru-. mentality composed of a plurality of sections scored from the box wall so as to be readily removable therefrom, a stationary die element formed of a plurality of sections includingan outer stationary section having a circular opening therein, a movable section substantially crescent-shaped in cross section within said opening, a stationary section shaped in cross section within said first crescentshaped section,'and second movable section Within said stationary crescent-shaped section, the exterior surface of the ring shaped section and the projected exterior surface of the stationary crescent shaped section being svbstantiailly tangent to the interior surface of said circular opening and to the projected exterior surface of the movable crescent shaped section at the same point, the outer surface of said second movable section following the extended exterior surface outline of said first movable section but leaving said extended outline to follow a smaller circular outline-at points short of the ends of said movable section, and a movable punch element formed of a plurality of similar and complementary sections with the sections on the punch cooperating with stationary die sectionsbeing movable relative to the main body of the punch and withthe sections on the punch cooperating substantially crescentwith movable die sections being stationary with respect to the main body of the punch, the relative movement between said sections being sufficient to produce at least a partial shearing of outer stationary section having a circular opening therein, a movable section substantially crescent-shaped in cross section within said opening, a stationary section substantially crescent-shaped in cross section within said first crescent-shaped section, a movable section substantially ring-shaped in cross section within said stationary crescent-shaped section, the exterior surface of the ring shaped section and the projected exterior surface of the stationary crescent shaped section being substantially tangent to the interior surface of said circular opening and to the projected exterior surface of the movable crescent shaped section at the same point, the outer surface of said ring-shaped section adjacent the point of tangency following theextended exterior surface outline of said first crescent-shaped section but leaving said extended outline to follow a circular outline parallel to its inner surface at points short of the ends of said first crescent-shaped section, and a stationary solid round section within said ring-shaped section, and a movable punch element formed of a plurality of similar and complementary sections with the sections on the punch cooperating with stationary die sections being movable relative to the main body of the punch and with the sections on the punch cooperating with the movable die sections being stationary with respect to the main body of the punch, the relative movement between said sections being sufiicient to produce at least a partial shearing of the sheet metal at the cutting edges of the sections, and additional die sections, not complemented in the punch element, disposed in the space between the ends of the first crescent-shaped die section and the third mentioned die section, the work metal adjacent these additional sections serving as unscored ties for the box wall outline formed by the inner crescent-shaped section.

6. In a punch and die tool for forming an opening providing means in a single pressing operation on a sheet metal box for an electric instrumentality composed of a plurality of sections scored from the box wall so as to be readily removable therefrom, a stationary die element formed of a plurality of sections including an outer stationary section having a circular opening therein, a movable section substantially crescent-shaped in cross section within said opening, a stationary section substantially crescent-shaped in cross section within said first crescent-shaped section, a movable section substantially ring-shaped in cross section within said stationary crescent-shaped section, the exterior surface of the ring shaped section and the projected exterior surface of the stationary crescent shaped section being substantially tangent to the interior surface of said circular opening and to the projected exterior surface of the movable crescent shaped section at the same point, the outer surface of said ring-shaped section following the interior surface of the opening in said first mentioned section but leaving said extended outline to follow a circular outline parallel to its inner surface at points short of the ends of said first crescent-shaped section, and a stationary solid round section within said ring-shaped section, and a movable punch element formed of a plurality of similar and complementary sections with the section on the punch cooperating with stationary die sections being movable relative to the main body of the punch and with the sections on the punch cooperating with the movable die sections being stationary with respect to the main body ofthe punch, the relative movement between said sections being suflflcient to produce at least a partial shearing of the sheet metal at the cutting edges of the sections, and additional die sections, not complemented in the punch element, disposed in the spaces between the ends of the first crescent-shaped die section and the fourth mentioned die section, the work metal adjacent these additional sections serving as unscored ties for a box wall section, and cutting edges on said additional die sections serving to nick the work metal on the line of the extended outline of said first crescent-shaped section to insure breaking of the tie on said line when the box wall section is removed.

7. In a punch and die tool for forming an opening providing means in a single pressing operation in a sheet metal box for an electric instrumentality composed of a plurality of sections scored from the box wall so as to be readily removable therefrom, a stationary die element formed of a plurality of sections including an outer section having a circular opening therein, a second section substantially crescent shaped in cross section within said opening, and at least a third section within said crescent shaped section, the extended interior outline of said crescent shaped section, eonforming to the exterior outline of .the section received therein, being substantially tangent to the interior surface of the circular opening, certain of said sections being relatively movable, and a movable punch element formed of a plurality of sections, similar and complementary to the sections on the die element, the sections on the punch cooperating with stationary die sections being movable relative to the main body of the punch and with the sections on the punch cooperating with movable die sections being stationary with respect to the main body of the punch, the relative movement between said sections being sufficient to produce at least a partial shearing of the sheet metal at the cutting edges of the sections.

8. In a punch and die tool for forming an opening providing means in a single pressing operation in a sheet metal box'for an electric instrumentality composed of a plurality of sections scored from the box wall so as to be readily removable therefrom, a stationary die element formed of a plurality of sections including an outer section having a circular opening therein, a second section substantially crescent shaped in cross section within said opening, and at least a third section within said crescent shaped section, the extended interior outline of said crescent shaped section, conforming to the exterior outline of the section received therein, being substantially tangent to the interior surface of the circular opening, certain of said sections being relatively movable, the outer surface of a section received within said crescent shaped section following the interior surface of the outer section a 2,240,188 5 for a. substantial distance; but leaving the surface oi said outer section to follow a smaller circular outline at points adjacent to the ends or said crescent shaped section, and a movable punch element-formed of a plurality of sections, similar and complementary to the sections on the die element, the sections on the punch cooperating with stationary die sections being movable relative to the main body of thepunch and with the sections on the punch cooperating with movable die sections beingstationary with respect to the main body 0! the punch, the relative movement between said sections being suillcient toproduce at least a partial shearing of the sheet metal at the cutting edges of the sections.

RALPH H. KINGDONZ GEORGE K. MOORE 

